Work on the final leg of the Purple Line Extension can now officially start.

Officials with the L.A. County Metropolitan Transportation Authority signed off on a $410 million contract on Thursday to build 2.6 miles of tunnels between Century City and the Veterans Administration hospital in Westwood.

The contract was awarded to the Sylmar-based construction firm Tutor Perini Corporation, according to a company press release.

Tutor expects to start work within 90 days and wrap up by the end of 2022. It’s the third and final phase of the Purple Line extension project. Construction started on phase 2 in February after the project secured Federal funding. Tutor is also working on that phase of the project.

While significant, the $410 million project is only part of the third phase of the extension project, which Metro estimates will take an additional four years to complete and open for service.

When completed, it would be the first Metro line to reach into Westwood, where the nearest existing heavy rail line is the Expo Line connecting Downtown to Santa Monica. It would give the neighborhood a direct shot to Downtown.

Altogether, the Purple Line extension will cost around $6.3 billion. It will be paid by tax hikes approved by voters in 2008 and 2016, the latter being Measure M.

The Purple Line could lead to denser development in the area, which is mostly characterized by single-family homes. It could incentivize developers to take advantage of density bonuses granted for building near transit and could attract people looking to commute to Downtown for work via public transit. And it could also ease traffic in the area.

The Purple Line could connect with a hypothetical 10-mile transit line connecting Sherman Oaks and Westwood via the Sepulveda Pass, a project proposed by Metro to ease traffic on Interstate 405 and the fumes from that traffic. Metro authorities are currently conducting a feasibility project.